The present invention relates to resin compositions for protective films, particularly, resin compositions for protective films for optical discs such as compact discs (CDs) and digital versatile discs (DVDs).
In these types of optical discs, the surfaces of exterior elements are normally coated to protect the surfaces of the exterior elements against scratches.
Effective materials for such coating are inorganic materials having high scratch resistance, but the inorganic materials have the disadvantage that coating solutions thereof are difficult to apply in a small thickness because of high viscosities.
In order to solve this problem, a conventional approach is to lower the viscosity of coating solutions by diluting solvents, but the diluted solutions erode substrates causing various problems.
For example, the substrate components are eluted, causing coating layers to lose flatness and therefore lose transparency (begin to appear matte).
Also, the eluted substrate components dissolve with the coating materials, so that scratch resistance is lowered.
Another possible approach to the above problem is to prepare a low viscosity coating solution using a low viscosity acrylate monomer as a reactive diluent in place of a solvent. When using this approach, however, scratch resistance may be considerably lowered depending on the monomer selected.